1. Technical Field
This disclosure relates generally to an aircraft propulsion system and, more particularly, to a nacelle for an aircraft propulsion system.
2. Background Information
A nacelle for an aircraft propulsion system is the structure surrounding the propulsion engine and provides a housing for the engine and ancillary systems and aerodynamic surfaces to reduce drag. A nacelle is configured with an inlet for directing air into the propulsion system. The nacelle inlet is also configured to begin guiding air around the exterior of the propulsion system in an aerodynamically efficient fashion. Active and passive laminar flow systems have been proposed for the exterior of the inlet to reduce the skin friction drag of the air passing around the exterior by maintaining laminar flow. However, any step or gap will cause the flow around the exterior to trip to turbulent flow. The split line between the inlet and the fan cowl (directly aft of the inlet) will trip the flow and, thus, it marks a practical boundary for the laminar flow region of the nacelle.